An electrodeless lamp or induction light is a gas discharge lamp in which the power required to generate light is transferred from outside the lamp envelope to the gas inside via electromagnetic fields, in contrast with a typical gas discharge lamp that uses internal electrodes powered by conductors that pass through the lamp envelope.
There are three advantages of eliminating electrodes:
Extended lamp life, because the electrodes are usually the limiting factor in lamp life.
The ability to use light-generating substances of higher efficiency that would react with metal electrodes in normal lamps.
Improved collection efficiency because the source can be made very small without shortening life, a problem in electroded lamps.